1. Field of the Invention
This invention relates to disposable molded articles such as eating utensils and tableware and to the production of expendable eating utensils and tableware for home, restaurant, catering, commercial and institutional use. More particularly, this invention relates to expendable cutlery and tableware with enhanced appearance, lower cost, improved safety and increased structural integrity.
2. Background
Disposable plastic eating utensils, sometimes referred to as disposable cutlery, are used extensively in restaurants, at home, in institutions, in commercial settings such as on airplanes, and for catered events because of the convenience they provide at a cost that is reasonably low to permit disposal after a single use. Currently, there are many types of disposable plastic cutlery ranging from barely functional inexpensive light-weight plastic cutlery to relatively expensive but higher-quality and more attractive cutlery styles.
Disposable cutlery articles are generally regarded as having a less-than-classic appearance which is not suited for an upscale presentation, while permanent cutlery, that is, metal cutlery is generally regarded as more upscale and as having a superior image but is, practically speaking too expensive to be disposable after a single use. This difference in perception is not entirely due to the superior strength of permanent cutlery. Although stainless steel cutlery or permanent cutlery is indeed stronger than disposable plastic cutlery, heavyweight plastic cutlery is functionally adequate for most occasions and may, after washing, even be reused. It is therefore still low enough in cost to be considered non-permanent but, rather, expendable in the sense of reusable for a limited time or a limited number of washings rather than disposable after a single use. Thus a primary obstacle to the use of disposable plastic cutlery in upscale situations is the perception and the image associated with disposable plastic cutlery rather than its actual performance.
One approach to enhancing the appeal of disposable plastic cutlery is to metalizing it. Metalized cutlery is described in U.S. Pat. No. 6,983,542 and US Patent Publications Nos. 2006/0191145 and 2010/0192388. These publications describe metalized plastic cutlery that replicates the appearance of genuine stainless steel cutlery.
Another way to enhance the appearance of disposable plastic items is to mold the articles in different colors or with different textures. A number of other references disclose disposable articles of cutlery or other products including the use of overmolding of different plastic or elastomeric materials to make the article. U.S. Pat. No. 6,634,877 and US Patent Publication No. 2002/0014720 disclose apparatus and methods for the injection overmolding of articles and the entire content of these documents is expressly incorporated herein by reference thereto as examples of the types of equipment and methods that are usable in the present invention along with the modifications disclosed herein.
A number of specific examples of molded articles follow.
U.S. Pat. No. 7,234,939 discloses a dental instrument made by two shot overmolding with polymers having different properties—one rigid and one elastomeric. The surface of the first polymer may be roughened to form an interlock with the second polymer. The dental instrument substrate is metal. An identifying character (618′ in FIG. 6B) may be molded of a first polymer and then surrounded by a second polymer of a different color.
U.S. Pat. No. 6,821,468 discloses the molding of two materials to form a handle. Lettering can be provided in one of the materials remote from the other material.
U.S. Pat. No. 6,368,536 discloses a tool handle injection molded of two different materials. Handle 11 is formed in a two-shot injection molding process, the inner body 20 being formed in the first shot and the outer gripping body 35 being formed in the second shot. The outer body completely surrounds the inner body.
U.S. Pat. No. 6,276,020 discloses a toothbrush made by molding a first material for strength and providing a pair of recesses for receiving a second material for aesthetics, wherein the second material in the recesses are separated by the first material.
U.S. Pat. No. 5,956,799 discloses a putty knife made of a first molded material with raised ribs of a second molded material.
U.S. Pat. No. 5,920,943 is directed to a co-injected paint brush having an outer softer layer and inner structure of harder material.
U.S. Pat. No. 5,615,445 discloses a putty knife made of a first molded harder material that is overmolded with a second softer material.
U.S. Pat. No. 5,290,063 discloses a two molded handgrip for a ski pole. The grip includes letters of a different color than the soft elastomeric material that surrounds the letters.
U.S. Pat. No. 4,535,014 discloses a multicolor two (or more) shot process for imparting different colored polymers into the handle of an article such as a toothbrush.
U.S. Pat. No. 4,422,995 discloses a method for injection-molding an elongate hollow workpiece about a central core wherein a first quantity of plastic is injected into a first mold cavity through which part of the core extends, to form a spacer element around the core. After the spacer element has hardened, the core and spacer element are transferred to a second mold cavity where another plastic is injected into the second mold cavity to complete the work-piece.
U.S. Pat. No. 2,335,872 discloses a molded cutlery item formed by placing a blade and molded handle assembly in a two-piece mold, one member of which is indicated at 40 (FIG. 4), the mold having a gate 42 and a vent 43. This mold is preferably of steel or other suitable metal. Metal for uniting the tang and handle is then poured through the gate 42. This metal is preferably an alloy of tin 55-60%, lead 40-45%, with a small quantity of antimony, and having a pouring temperature not in excess of about 400-450° F. The metal flows around the blade and handle, as seen in FIG. 4, flowing down from the bolster into the bore of the handle, filling the bore around the tang and flowing out of the bore through the apertures 28 so as to form rivets 20.
US Patent Publication No. 2011/0219631 discloses plastic cutlery of first and second parts joined together. The first part is a food contacting part of a first food-grade resin, that may be metallized; the second part is a non-food-contacting part of a non-food grade resin that may be pigmented. The first part may be of a first resin that is co-extruded with an antimicrobial-containing outer layer. The food contacting part is inserted into the non-food contacting part.
US Patent Publication No. 2009/0144991 discloses a utensil head that is pivotally connected to a shaft, such that the utensil head articulates between unfolded and folded positions.
US Patent Publication No. 2009/0119860 discloses an article having a riveted joint, in which the components that are joined together are movable with respect to one another in a plane perpendicular to the rivet.
US Patent Publication No. 2007/0079685 discloses a guitar pick that includes a body 40 that has void 45 (e.g. as shown in FIG. 7), which can be a closed bore or a through bore. Body 30 can have boss 36 which can form letters or other indicia, for example as shown in FIGS. 5 and 6, projecting from body 30 and matingly engaged within void 35, such as shown in FIG. 5. Void 45 and boss 36 can have corresponding shapes or different shapes. The boss is surrounded by molding material.
Despite these disclosures, there still remains a growing demand for even more attractive, yet sanitary, disposable articles such as cutlery that can be efficiently and effectively produced, and these are now provided by the present invention.